Are there any specific precautions one should take when adding variables to SQL queries in PHP?

When adding variables to SQL queries in PHP, it is important to use prepared statements to prevent SQL injection attacks. Prepared statements separate the SQL query logic from the data being passed, ensuring that user input is treated as data rather than executable code. 

// Example of using prepared statements to add variables to SQL queries in PHP
$pdo = new PDO('mysql:host=localhost;dbname=mydatabase', 'username', 'password');

// Prepare a SQL query with a placeholder for the variable
$stmt = $pdo->prepare('SELECT * FROM users WHERE username = :username');

// Bind the variable to the placeholder
$stmt->bindParam(':username', $username);

// Execute the query
$stmt->execute();

// Fetch the results
$results = $stmt->fetchAll();

Keywords

SQL injection prepared statements PDO mysqli_real_escape_string parameterized queries

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